Physical Sciences and Mathematics Commons^™

Morphology And Mixing State Of Soot And Tar Balls: Implications For Optical Properties And Climate, Janarjan Bhandari

Dissertations, Master's Theses and Master's Reports

Soot particles form during incomplete combustion of carbonaceous materials. These particles strongly absorb light and directly affect Earth’s climate by warming our atmosphere. When freshly emitted, soot particles have a fractal-like morphology consisting of aggregates of carbon spherules. During atmospheric processing, soot aggregates interact with other materials present in our atmosphere (i.e., other aerosol or condensable vapors) and these interactions can result in the formation of coated, mixed or compacted soot particles with different morphologies. Any process that alters the morphology (shape, size and internal structure) and mixing state of soot also affects its optical properties, which in turn affect …

Investigation Of Microphysical Properties Of Laboratory And Atmospheric Clouds Using Digital In-Line Holography, Neel Desai

Dissertations, Master's Theses and Master's Reports

In this study, we attempt to perform in-cloud measurements, both in the laboratory using the Michigan Tech $\Pi$-chamber and in the atmosphere via the CSET field campaign. Atmospheric turbulence is believed to play a critical role in the growth, development and dissipation of clouds and it is important to study its effect in order to better understand and predict cloud properties such as albedo and lifetime. We use digital in-line holography to measure the effect of turbulence on cloud microphysical properties such as variations in droplet number concentration and droplet or ice particle size. In the first half, we study …

Algorithms For Reconstruction Of Gene Regulatory Networks From High -Throughput Gene Expression Data, Wenping Deng

Dissertations, Master's Theses and Master's Reports

Understanding gene interactions in complex living systems is one of the central tasks in system biology. With the availability of microarray and RNA-Seq technologies, a multitude of gene expression datasets has been generated towards novel biological knowledge discovery through statistical analysis and reconstruction of gene regulatory networks (GRN). Reconstruction of GRNs can reveal the interrelationships among genes and identify the hierarchies of genes and hubs in networks. The new algorithms I developed in this dissertation are specifically focused on the reconstruction of GRNs with increased accuracy from microarray and RNA-Seq high-throughput gene expression data sets.

The first algorithm (Chapter 2) …

Determination Of Organic Acid Preservatives In Shrimp Paste By Headspace Solid-Phase Microextraction Combined With Gas Chromatography, Nuttanee Tungkijanansin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Organic acids, which are benzoic acid, sorbic acid and propionic acid, are the most common preservatives used in foods and have been regulated the usage. Shrimp paste, called Kapi in Thai, is a fermented food that used in many Thai dishes. Owing to a complex matrix in shrimp paste, sample preparation is required to determine the amount of organic acid preservatives in shrimp paste. In this work, headspace solid-phase microextraction (HS-SPME) was developed for extraction of organic acid preservatives in shrimp pastes and analyzed by gas chromatography with flame ionization detector (GC-FID). The 85 µm polyacrylate coated fiber was used …

Paper-Based Analytical Device For Determination Of Triglycerides, Yolthida Kantapa

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, a paper-based analytical device (PAD) together with enzymatic reactions was developed for determination of triglycerides using colorimetric detection. The method was based on the enzymatic reactions between triglycerides and enzymes (lipase, glycerol kinase and glycerol-3-phosphate oxidase). Hydrogen peroxide which was generated from the enzymatic reactions is reduced by chromogenic substrates which were 3-methyl-2-benzothiazolinone hydrazone (MBTH) and 3-(dimethylamino)benzoic acid (DMAB) in the presence of peroxidase to produce an indamine dye. The blue color intensity of indamine dye is directly proportional to triglycerides concentration. For quantitative analysis, the interfering effect of ascorbic acid in real samples was eliminated using …

Positively Charged Particles From Amphiphilic Chitosan For Plasmid Dna Delivery, Tinnakorn Phuangkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

Amphiphilic chitosan derivatives have been well regarded as potential non-viral vectors for gene delivery. Their hydrophobic entities could promote cell permeability whereas their hydrophilic entities especially those carrying positive charges can interact with the negatively charged phosphate groups of DNA. Here in this research, a series of amphiphilic chitosan derivatives were synthesized. Linear hydrocarbon of two different chain length: hexyl (C6) and dodecyl (C12) were substituted at amino groups of chitosan via reductive alkylation with hexanal and dodecanal and yielded two hydrophobized chitosan derivatiives, hexyl chitosan (HCS) and dodecyl chitosan (DCS), respectively. Phthaloyl chitosan (PhCS) was also prepared as another …

Reduced Graphene Oxide-Modified Screen-Printed Carbon Electrode For Determination Of Homocysteine Using Catechol, Suchapa Naranaruemol

Chulalongkorn University Theses and Dissertations (Chula ETD)

Homocysteine (Hcy), also known as 2-amino-4-mercaptobutyric acid, is a biomarker that is directly associated with an increased risk of cardiovascular diseases (CVDs). In this work, catechol (CA), which is redox active, had been used as an electron transfer mediator to facilitate the oxidation of Hcy. Typically, CA was first electrochemically immobilized onto the surface of screen-printed carbon electrode; however, the obtained CA-functionalized electrode did not show the electrocatalytic activity towards the detection of Hcy. Therefore, the deter– mination of Hcy was investigated in the solution containing CA using differential pulse voltammetry (DPV) at the reduced graphene oxide-modified screen-printed carbon electrode …

Synthesis And Biological Activities Of Halogenated Chalcone-Based Pyra, Dinh Phuoc Nguyen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Twenty new 1,3,5-trisubstituted pyrazoline derivatives have been synthesized from chalcones and acylhydrazides in two steps. In the first step, chalcones were prepared by treatment of various acetophenones with different substituted benzaldehydes by Claisen-Schmidt condensation. In the second step, pyrazoline derivatives were synthesized by conducting the reaction of chalcones with acylhydrazides in acetonitrile at 67 °C in the presence of triazabicyclodecene as a catalyst. The synthesized compounds were identified by 1H, 13C NMR and HRMS spectral data and were evaluated for their antibacterial, anticancer and tyrosinase inhibitory activities. In antibacterial and tyrosinase inhibitory activities, most of pyrazoline derivatives showed inactive properties. …

Modification Of Screen-Printed Carbon Electrode With Mxene/Conductive Polymer Composites For Hydrogen Peroxide Detection, Supawat Neampet

Chulalongkorn University Theses and Dissertations (Chula ETD)

MXene (Ti3C2), a two-dimensional material consisting of transition metal carbides, nitrides or carbonitrides was prepared by etching method for modification electrode of a novel nanocomposites consisting of platinum nanoparticles (PtNPs) and polyaniline (PANI) via electrodeposition and electropolymerization, respectively. The fabricated MXene/PANI/PtNPs nanocomposite modified on surface screen-printed carbon electrode (SPCE) were characterized by scanning electron microscopy SEM) with energy dispersive X-rays spectroscopy (EDX), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM) to verify the presence of nanocomposite materials and indicate their morphologies. This electrode was applied for the detection of hydrogen peroxide (H2O2), which is a common electroactive product from …

ผลของสารลดแรงตึงผิวต่อการเตรียมตัวเร่งปฏิกิริยา Ptco/C สําหรับปฏิกิริยารีดักชันของออกซิเจน ในเซลล์เชื้อเพลิงพีอีเอ็ม, ปาณิศา ปราบ ณ ศักดิ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาผลของสารลดแรงตึงผิวที่มีต่อตัวเร่งปฏิกิริยา PtCo/C สำหรับปฏิกิริยารีดักชันของออกซิเจนในเซลล์เชื้อเพลิงพีอีเอ็ม ซึ่งสารลดแรงตึงผิวที่ใช้ในการทดลองประกอบด้วย สารลดแรงตึงผิวชนิดประจุบวก (CTAB), ชนิดประจุลบ (SDS), และชนิดไม่มีประจุ (Triton X-100) โดยทำการเตรียมตัวเร่งปฏิกิริยา PtCo/C ร้อยละ 20 โดยน้ำหนัก ผลการทดลองพบว่าตัวเร่งปฏิกิริยาที่ใช้ CTAB ความเข้มข้น 0.004 โมลต่อลิตร ให้พื้นที่ผิวในการเกิดปฏิกิริยาเคมีไฟฟ้าสูงที่สุด นอกจากนี้การปรับปรุงตัวเร่งปฏิกิริยาด้วยความร้อนที่อุณหภูมิ 600 องศาเซลเซียส สามารถเพิ่มพื้นที่ผิวในการเกิดปฏิกิริยาและช่วยลดขนาดอนุภาคของตัวเร่งปฏิกิริยาลงได้ เนื่องจากการปรับปรุงด้วยความร้อนจะกำจัดสารลดแรงตึงผิวที่บดบังบริเวณการเกิดปฏิกิริยา การศึกษาเสถียรภาพของตัวเร่งปฏิกิริยาในสารละลายกรดซัลฟิวริกที่อิ่มตัวด้วยไนโตรเจน ความเข้มข้น 0.5 โมลต่อลิตร พบว่า CTAB ความเข้มข้น 0.004 โมลต่อลิตร มีเสถียรภาพสูงที่สุด รองลงมาเป็น Triton X-100 และ SDS ตามลำดับ ซึ่งเป็นผลมาจากปริมาณพื้นที่ผิวในการเกิดปฏิกิริยาของตัวเร่งปฏิกิริยา ส่วนของการทดสอบกัมมันตภาพสำหรับปฏิกิริยารีดักชันของออกซิเจนในสารละลายกรดที่อิ่มตัวด้วยออกซิเจนและเซลล์เชื้อเพลิงพีอีเอ็มแบบเซลล์เดี่ยวภายใต้ภาวะไฮโดรเจน/ออกซิเจน ที่อุณหภูมิ 60 องศาเซลเซียส ความดันบรรยากาศ พบว่า Triton X-100 ความเข้มข้น 0.001 โมลต่อลิตร ให้กัมมันตภาพในสารละลายกรดและเซลล์เชื้อเพลิงพีอีเอ็มแบบเซลล์เดี่ยวสูงที่สุด

Covers For Unit Arcs, Sutara Patlertsin

Chulalongkorn University Theses and Dissertations (Chula ETD)

In 1966, Leo Moser posed a famous problem asking “ What is the region of smallest area which will accommodate every planar arc of length one? ". In 2003, Norwood and Poole showed that the cover whose upper boundary is the circular arc and the lower boundary is composed of 2 symmetric parabolic arcs between 2 symmetric circular arcs is the smallest cover known which are not convex. In this work, we study the region obtained by modifying the cover of Norwood and Poole and its area is 0.2596605. We investigate the Λ-property and relating properties which are very useful …

Automating Ciri Ratings Of Human Rights Reports Using Gate, Joshua M. Joiner

UNF Graduate Theses and Dissertations

This thesis involves parsing document-based reports from the United States Human Rights Reports and rating the human practices for various countries based on the CIRI (Cingranelli-Richards) Human Rights Data Project dataset. The United States Human Rights Reports are annual reports that cover internationally recognized human rights practices regarding individual, civil, political, and worker rights. Students, scholars, policymakers, and analysts used the CIRI data for practical and research purposes. CIRI analyzed the annual reports from 1981 to 2011 and then stopped releasing the dataset for any further years, but a possible reason is due to the manual process of scouring the …

Detection Of Cyanotoxins (Microcystins/Nodularins) In Hepatic Tissues And Epidermal Mats Of Stranded Bottlenose Dolphins (Tursiops Truncatus) In Northeast Florida, Amber Brown

UNF Graduate Theses and Dissertations

The St. Johns River (SJR; Jacksonville, FL, USA) is a large, brackish, estuarine system characterized by considerable anthropogenic pollution, recurrent harmful algal blooms (HABs), and diverse toxin-producing cyanobacteria. The most prevalent toxins in SJR water samples are microcystins/nodularins (MCs/NODs). Additionally, the SJR provides critical habitat for a genetically and behaviorally distinct estuarine community of bottlenose dolphins (Tursiops truncatus) that routinely uses and strands in low mesohaline and oligohaline areas of the river. This population has been subject to two unusual mortality events (UME) since 2010 and has since been described as having substantial declines in population health, characterized …

Particle Filters For State Estimation Of Confined Aquifers, Graeme Field

UNF Graduate Theses and Dissertations

Mathematical models are used in engineering and the sciences to estimate properties of systems of interest, increasing our understanding of the surrounding world and driving technological innovation. Unfortunately, as the systems of interest grow in complexity, so to do the models necessary to accurately describe them. Analytic solutions for problems with such models are provably intractable, motivating the use of approximate yet still accurate estimation techniques. Particle filtering methods have emerged as a popular tool in the presence of such models, spreading from its origins in signal processing to a diverse set of fields throughout engineering and the sciences including …

Investigation Of Near-Bottom Current Characteristics Along An Open-Ocean Coast, Nikole S. Ward

UNF Graduate Theses and Dissertations

Near-bottom current data was collected over a period of 8 years at the U.S. Army Corps of Engineers Field Research Facility in Duck, North Carolina. This data set consisted of currents measured up to three elevations above the bottom at deployment depths of 5 meters, 8 meters and 13 meters, as well as continuous real-time wind and wave data collected at the pier. The data was collated, quality checked and analyzed to define a climatology of near bottom currents along the study area using current moments. This data set had previously never been available for analysis due to the large …

A Consideration Of Mason’S Ethical Framework: The Importance Of Papa Factors In The 21st Century: A Seven-Year Study, Katharine Creevey Brown

UNF Graduate Theses and Dissertations

Richard Mason proposed a social framework for addressing the major ethical issues of the information age in his pivotal 1986 article “Four Ethical Issues of the Information Age.” In 2006, Alan Peslak validated the framework by measuring the current attitudes of students, IT professionals, and university faculty and staff toward the four key issues proposed by Mason: privacy, accuracy, property, and accessibility (referred to as PAPA). This study continues this inquiry into the seven-year period after Peslak’s research. Previously collected data was analyzed for 312 university computing majors taking a senior-level ethics course where Mason was taught and discussed. Demographic …

Seismic Anisotropy And The Mantle Dynamics Beneath The Arabian Plate, Saleh Ismail Hassan Qaysi

Doctoral Dissertations

"We investigate mantle seismic azimuthal anisotropy and deformation beneath the Arabian Plate and adjacent areas using data from 182 broadband seismic stations which include 157 stations managed by the Saudi Geological Survey. A total of about 4000 pairs of shear wave splitting parameters are obtained using the transverse minimization technique. The individual XKS (including PKS, SKS, and SKKS) splitting measurements were manually checked to ensure the quality. The well-defined parameters show dominantly N-S fast orientations at the majority of the stations, and NW-SE fast orientations along the Zagras Mountain front. No clear systematic variations of the splitting parameters as a …

Phenolic Resin Aerogels: The Significance Of Inserting An Oxidative Ring-Fusion Aromatization Step At The Early Stages Of Pyrolytic Carbonization, And The Application Of These Materials In Co₂ Storage And Separation, Hojat Majedi Far

Doctoral Dissertations

"Phenolic aerogels, prepared via polycondensation of phenolic monomers and formaldehyde, were converted to carbon aerogels at 800 ⁰C/Ar followed by reactive etching under flowing CO₂. Previously, it was found that a lower-temperature air-oxidation of polybenzoxazine aerogels was necessary in order to obtain highly porous, isomorphic carbon aerogels with high carbonization yields. Using those findings as the point of departure, phenolic aerogels were oxidized at 240 ⁰C/air prior to carbonization. During that air-oxidation step, phenolic aerogels based on phloroglucinol (1,3,5- trihydroxybenzene) undergo fusion of their aromatic rings, yielding 6-membered heteroaromatic pyryliums with pendant phenoxide ions. The resulting carbon aerogels …

Correlation Between Delay Time And Measured Concentration And Concentration Uncertainty By Neutron Activation Analysis, James Thomas Seman

Doctoral Dissertations

"For the last several decades, it has been apparent that new methods of identifying explosives can help investigators trace their origins. One way to identify an explosive is through the use of taggants: materials added to a product that encodes information about the product such as when it was manufactured.

This research investigates the survivability of a new identification taggant called the Nuclear Barcode that overcomes some of the downfalls that have been identified in prior taggants. The Nuclear Barcode encodes information as a unique combination of concentrations of rare earths (Ho, Eu, Sm, Lu, and Dy) and precious metals …

Modeling And Characterization Of Thermo-Oxidative Behavior Of Bismaleimide Composites, Rafid Muhammad Hussein

Doctoral Dissertations

"High-temperature polymer matrix composites (HTPMCs) are susceptible to thermo-oxidation, which accelerates the composites' degradation and reduces the service life. Mechanical properties of HTPMCs deteriorate due to coupled thermo-oxidation and cross-linking mechanisms. Bismaleimides (BMIs) are commonly used high-temperature resins for aerospace applications. This work presents the viability of using experimental weight loss to model the spatial distribution of oxidation when the oxidized polymer matrix is not discernible. Three tasks are introduced: (1) Anisotropic oxidation prediction using optimized weight loss behavior of bismaleimide composites, (2) A multi-scale modeling of thermo-oxidative effects on the flexural behavior of cross-ply bismaleimide composites, and (3) Thermo-oxidative …

Functionalized Nanoporous Carbon Scaffolds For Hydrogen Storage Applications, Christopher L. Carr

Doctoral Dissertations

"Recent efforts have demonstrated confinement in porous scaffolds at the nanoscale can alter the hydrogen sorption properties of metal hydrides, though not to an extent feasible for use in onboard hydrogen storage applications, proposing the need for a method allowing further modifications. The work presented here explores how the functionalization of nanoporous carbon scaffold surfaces with heteroatoms can modify the hydrogen sorption properties of confined metal hydrides in relation to non-functionalized scaffolds (FS). Investigations of nanoconfined LiBH₄ and NaAlH₄ indicate functionalizing the carbon scaffold surface with nitrogen can shift the activation energy of hydrogen desorption in excess of …

New Developments Of Dimension Reduction, Lei Huo

Doctoral Dissertations

"Variable selection becomes more crucial than before, since high dimensional data are frequently seen in many research areas. Many model-based variable selection methods have been developed. However, the performance might be poor when the model is mis-specified. Sufficient dimension reduction (SDR, Li 1991; Cook 1998) provides a general framework for model-free variable selection methods.

In this thesis, we first propose a novel model-free variable selection method to deal with multi-population data by incorporating the grouping information. Theoretical properties of our proposed method are also presented. Simulation studies show that our new method significantly improves the selection performance compared with those …

Crustal Structure Beneath The Eastern Margin Of The Tibetan Plateau And Adjacent Areas From Receiver Function Stacking And Gravity Modeling, Yunxin Peng

Doctoral Dissertations

"To provide constraints on the mechanisms responsible for the uplift and crustal thickening of the eastern Tibetan Plateau, the thickness and Vp/Vs values of the Moho beneath 153 seismic stations are obtained by stacking P-to-S converted phases from the Moho and gravity modeling. The resulting crustal thickness generally decreases from the northwest to the south-east, from about 60 km in the Bayan Har Block to 30 km in the Sichuan Basin. The crustal Vp/Vs measurements in the Qinling Orogenic Belt, Bayan Har Block, Chuxiong Basin, and Yangtze Platform indicate an overall intermediate to felsic crustal composition. With a relatively thick …

Security Risk Assessment In Cloud Computing Domains, Amartya Sen

Doctoral Dissertations

"Cyber security is one of the primary concerns persistent across any computing platform. While addressing the apprehensions about security risks, an infinite amount of resources cannot be invested in mitigation measures since organizations operate under budgetary constraints. Therefore the task of performing security risk assessment is imperative to designing optimal mitigation measures, as it provides insight about the strengths and weaknesses of different assets affiliated to a computing platform.

The objective of the research presented in this dissertation is to improve upon existing risk assessment frameworks and guidelines associated to different key assets of Cloud computing domains - infrastructure, applications, …

3d Seismic Attribute Analysis And Machine Learning For Reservoir Characterization In Taranaki Basin, New Zealand, Aamer Alhakeem

Doctoral Dissertations

"The Kapuni group within the Taranaki Basin in New Zealand is a potential petroleum reservoir. The objective of the study includes building a sequential approach to identify different geological features and facies sequences within the strata, through visualizing the targeted formations by interpreting and correlating the regional geological data, 3D seismic, and well data by following a sequential workflow. First, seismic interpretation is performed targeting the Kapuni group formations, mainly, the Mangahewa C-sand and Kaimiro D-sand. Synthetic seismograms and well ties are conducted for structural maps, horizon slices, isopach, and velocity maps. Well log and morphological analyses are performed for …

Paleogene-Early Neogene Palynomorphs From The Eastern Equatorial Atlantic And Southeastern Florida, Usa: Biostratigraphy And Paleoenvironmental Implications, Walaa K. Awad

Doctoral Dissertations

"The transition from greenhouse conditions (Paleocene-Eocene Thermal Maximum, PETM) to icehouse conditions (Early Oligocene) is not well documented in tropical-subtropical regions. One hundred and five samples from Ocean Drilling Program (ODP) Site 959 (Hole 959A and Hole 959D) in the Cote d'Ivoire-Ghana Transform Margin, Alo-1 Well in the northern Niger Delta (Anambra) Basin, Nigeria, and W-17001 in southeastern Florida were studied for their palynological contents. Dinoflagellate cysts were mainly utilized for age refinement and to detect subtle changes in paleoenvironment and paleoclimate during the Paleocene-Early Eocene (ODP Hole 959D and Alo-1 Well) and Late Eocene-Early Miocene (ODP Hole 959A and …

Incremental Proper Orthogonal Decomposition For Pde Simulation Data: Algorithms And Analysis, Hiba Fareed

Doctoral Dissertations

"We propose an incremental algorithm to compute the proper orthogonal decomposition (POD) of simulation data for a partial differential equation. Specifically, we modify an incremental matrix SVD algorithm of Brand to accommodate data arising from Galerkin-type simulation methods for time dependent PDEs. We introduce an incremental SVD algorithm with respect to a weighted inner product to compute the proper orthogonal decomposition (POD). The algorithm is applicable to data generated by many numerical methods for PDEs, including finite element and discontinuous Galerkin methods. We also modify the algorithm to initialize and incrementally update both the SVDand an error bound during the …

Aerogels For Energy Storage Applications: From Shape Memory Materials To Thermites And Explosives, Suraj Donthula

Doctoral Dissertations

"Aerogels are three dimensional highly porous solid objects that provide density reduction compared to dense objects. Those materials can have applications in different classes of energy storage and the two types that are focused in this dissertation are mechanical energy and thermal energy storage. Shape memory materials can store and recover elastic deformation energy when triggered by an external stimulus such as temperature. To incorporate those properties, shape memory polymeric aerogels (SMPA) were synthesized from a rigid isocyanurate containing triisocyanate (N3300 A) and four short oligomeric derivatives of ethylene glycol: H(OCH₂CH₂)_nOH (1 ≤ n …

Cox-Type Model Validation With Recurrent Event Data, Muna Mohamed Hammuda

Doctoral Dissertations

"Recurrent event data occurs in many disciplines such as actuarial science, biomedical studies, sociology, and environment to name a few. It is therefore important to develop models that describe the dynamic evolution of the event occurrences. One major problem of interest to researchers with these types of data is models for the distribution function of the time between events occurrences, especially in the presence of covariates that play a major role in having a better understanding of time to events.

This work pertains to statistical inference of the regression parameter and the baseline hazard function in a Cox-type model for …

Evolving Specialization In An Agent-Based Model Without Task-Switching Costs, Shane Robert Meyer

Doctoral Dissertations

"This work examines the possibility of evolving the phenotypic specialization associated with division of labor in an agent-based model without task-switching costs. The model examines two groups competing for vital resources, where members of one group are capable of sharing resources with other agents in their group. Agents attempt to collect resources which allow them to reproduce, with more resources leading to a greater number of offspring by asexual reproduction. Four variants of the model are examined, with combinations of one or two resources and the presence of a foraging risk. The presence of the foraging risk can lead to …